Influence of crosslinking effect on chemical and rheological properties of aged liquid bio-rubber composite SBS modified asphalt

AbstractThe influence of the cross-linking effect between a liquid bio-rubber (LBR), a desulphurised crumb rubber formed via pyrolysis in bio-oil, SBS, a cross-linker, and asphalt on the chemical and rheological properties of aged LBR/SBS composite modified asphalt (LBR/SBSMA) was studied. Four types of modified asphalts were prepared by adding LBR, LBR+sulphur, LBR+SBS and LBR+SBS+sulphur to simulate cross-linking. FTIR and GPC were used to obtain oxidation, aromatisation and polymer degradation indexes and molecular weight. DSR and BBR were used to acquire rheological indexes. Sulphur was the key factor in achieving cross-linking, which promoted phase morphology stability, enhanced oxidation and aromatisation resistance and restrained polymer degradation. LBR could prevent the variation of |G*| and the change of δ in high frequency after ageing. The low-temperature performance of aged LBR asphalt was satisfactory. The cross-linking effect retained superior ageing resistance despite a slight impairment of low-temperature continuous grading temperature, producing a sustainable and high-performance modified asphalt.KEYWORDS: Composite modified asphaltliquid bio-rubbercrosslinkingageing mechanismchemical structurerheology Disclosure statementNo potential conflict of interest was reported by the author(s).Additional informationFundingThis work was supported by National Natural Science Foundation of China: [Grant Number 51578097]; Chongqing Doctoral "Through Train" Research Project: [Grant Number 2022BSXM-JCX0169]; Natural Science Foundation of Chongqing: [Grant Number CSTB2022NSCQ-MSX1269]; Technology Cooperation Project (2023) of Guizhou Province: [Grant Number General 299].